Sugar… is it all that bad?

Evolutionary biologists believe that humans are programmed to search out sugary foods. Historically, food scarcity would have been common and during these times finding sugary food would have meant the difference between life and death.

In modern times, however, excessive sugar intake is a major threat to our health and well-being. The World Health Organization recommends an intake of less than 5% of added sugar, and at this level, the average person who consumes 1800kcal per day would have no more than 22.5g of added sugar. Bear in mind that most cans of soft drinks can contain 40 grams of added sugar!

The generic term, sugar, refers to carbohydrates, found in fruits, vegetables, grains, and milk, amongst other foods. The term added sugar refers to non-intrinsic sugars, meaning sugar that has been added during the processing or production of a food or drink. There is a proven association between intakes of added sugars and increased dental problems such as; dental cavities, infection, and inflammation [i]. But the negative impact of sugar consumption goes deeper than this.

What happens when sugar is ingested?

In the most part, added sugars consist of glucose and fructose; with honey being 55% fructose and 45% glucose; white table sugar is 100% sucrose, which is 50% fructose and 50% glucose. Glucose is the bodies preferred energy source and fructose can be converted to glucose if required. When sugar is consumed, the pancreas acts as the gatekeeper, deciding its fate; either it is used immediately as energy, or it is stored. If the sugar entering the blood is not required to power our energy expenditure, the pancreas secretes the hormone, insulin, which engineers the storage of sugar in our cells or in the liver.

Some sugary drinks contain 40g of sugar which is way in excess of what the body requires, unless said person is running a marathon at the time!

If our body is functioning efficiently, sugar is used for energy with any excess being stored in cells, or in the liver as glycogen, a stored form of glucose that can be accessed later. One issue is the speed at which sugar enters the blood supply. With some sugary drinks containing 40g of sugar with no other beneficial nutrients, the sugar rapidly enters the blood, so insulin is secreted at great volume to reduce the impact of this sugar ‘hit’ and the excess is stored as fat, resulting in weight-gain.

Blood sugar:

The spike in blood sugar following high intakes of sugary foods or drinks are accompanied by a subsequent dip, and since sugar is the primary food for the brain, it is dangerous for blood sugar to drop low. The result is cravings for more sugar, creating another spike in blood sugar and subsequent dip, sending the individual on a roller-coaster ride in terms of energy and appetite.

All this time the pancreas continues to secrete insulin, and if this pattern of overstimulation continues insulin resistance can develop sending the individual on the path towards a number of health conditions known as metabolic syndrome which involves abnormal cholesterol or triglyceride levels, high blood pressure, heart disease, stroke, obesity, high blood sugar, and type-2-diabetes.

Stable versus unstable blood sugar, with the unstable blood sugar being described as a roller-coaster ride in terms of energy and appetite.

The impact of high-sugar diets on insulin levels has another detrimental effect since high insulin interferes with the function of leptin, the hormone that regulates our appetite and fat storage. Overstimulation of insulin results in the body becoming less sensitive to leptin, meaning the message that we are full does not reach the brain. It is then common to over-consume calories, paving the path for overweight and obesity.

Measuring the impact of sugar:

We can map the impact of different foods and drinks by checking the glycaemic index; this classifies the food or drink according to speed at which that food increases blood sugar. Foods classified as 0 have a negligible effect, and those classified as 100, have a strong effect. Glucose has a value of 100. Fructose, on the other hand, has a much lower glycaemic index of 30 because it follows a different pathway to glucose and is metabolized by the liver. For this reason, fructose is seen as a good sweetener for diabetics helping them to manage blood sugar. But fructose has its own drawbacks.


Fructose is strongly associated with fat storage, with large amounts being transformed by the liver into triglycerides; storage fat cells. Elevated triglycerides are a risk factor for cardiovascular disease. Fructose is present in fruit, vegetables, and honey, but is always present in nature as a combination with glucose. Even high-fructose corn syrup is not as high in fructose as the name would suggest, usually containing 55% fructose to 45% glucose. Studies show that excessive consumption of added fructose can result in increased visceral fat, a dangerous type of fat accumulating around the abdomen and internal organs, such as the liver and heart. Elevated visceral fat leads to inflammation and increased risk of inflammatory conditions.

Visceral fat, a dangerous type of fat accumulating around the abdomen and internal organs.

The Good News:

The good news is that the negative impact of both fructose and glucose on the body is dose dependent. When we eat nutritious foods that contain sugars, the sugar is absorbed slowly. Researchers looking at adverse effects of dietary fructose found that serum fructose rose by a negligible amount following consumption of whole-foods containing fructose [ii]. When consuming sugars in food, the fat and protein content of that food slow down the absorption of the sugar and its impact on the body. In terms of dental caries, frequency is considered to be the determining factor; whereby having a sugary snack once a day might be fine, eating foods with added sugars frequently throughout the day is associated with higher risk [iii].

There are alternatives to white sugar, with stevia, xylitol, coconut sugar and organic honey all being arguably better than their highly refined counterparts.


Stevia, sometimes referred to as E 960, is a 100% natural, refined powder made from an extract of the leaves of Stevia Rebaudiana and is 200 to 300 times sweeter than white table sugar [iv].  Technically, stevia is not a sugar, but a naturally sourced nutritive sweetener boasting many benefits over white sugar; it is considerably sweeter, meaning less is required to sweeten recipes; it contains zero calories; it is not damaging to teeth; and substituting sugar for stevia has been found to benefit skin problems like eczema and dermatitis.

Stevia consumption has also been found to reduce blood pressure and blood sugar, whilst increasing blood glucose tolerance in some clinical trials. The successful trials tended to be longer-term studies, with single-dose studies showing less impact, suggesting that regular consumption gives the best results [v].

An impressive résumé!

There are certain drawbacks in that the texture and taste of stevia is quite different to sugar. Since stevia is so much sweeter than sugar, when substituting it in recipes you need significantly less stevia. For the best results, use recipes created with stevia in mind, or try combining stevia with another sugar alternative, like coconut sugar.


Xylitol is a naturally occurring sugar alcohol made from an extract of birch or beechwood or the fibrous parts of plants. Previously this sugar was mostly found in commercially prepared foods, but is becoming more popular as a sugar substitute to use at home. Xylitol boasts;

  • similar sweetness to white table sugar;
  • comparable texture and taste to white table sugar;
  • contains 40% less calories than white table sugar;
  • exerts a negligible effect on insulin and blood sugar levels;
  • has a low glycaemic index of only 7, and;
  • is not damaging to teeth
  • it may improve calcium absorption and could therefore be protective against osteoperosis.

You really can have your cake and eat it!    

Xylitol sweetened chewing gum has been researched extensively since 1970 for its benefits to oral health. Research has consistently shown that xylitol sweetened chewing gum inhibits the development of dental issues and therefore improves oral health since it neutralizes acids in the mouth which cause dental caries.

The main drawback of xylitol is that in large quantities it can have a laxative effect, however research shows that most adults tolerate quantities of up to 40g per day without side effects.

Coconut sugar:

Coconut sugar is made from sap extracted from flowers of the coconut palm using little processing and resulting in a very pure form of sugar. Because processing is minimal, the sugar retains small quantities of trace minerals such as; calcium, potassium, sodium, iron and zinc. Antioxidants such as polyphenols and ascorbic acid have also been identified in coconut sugar, along with approximately 5% of the dietary fibre, inulin, a soluble fiber commonly used in probiotic supplements because it stimulates the growth of beneficial bacteria in the gut.

Coconut sugar has a lower sucrose content than white table sugar and a lower glycaemic index, although reliable data is not available to quantify the exact index score. The reduction in glycaemic index is thought to be due to the fibre content along with certain proteins contained in coconut sap, which can slow down the metabolism and digestion of sugars [vi]. Most of all, coconut sugar tastes great and is probably the easiest alternative to switch to in recipes.

Organic honey:

Organic honey is the pure, unprocessed sweet liquid made by bees from the nectar of flowers. Since ancient times honey has been considered a medicine, used for healing wounds and burns, for aiding digestive disorders, and for supporting immunity. Organic honey contains vitamins and minerals, but its strength lies in its a rich content of antioxidant molecules such as phenolic acids and flavonoids [vii]. The PubMed database holds thousands of research papers on honey and its antioxidant, antimicrobial, antiviral, antifungal, anticancer and antidiabetic actions, to name just a few.

Studies have demonstrated benefits of honey consumption for individuals with diabetes, such as improving fat metabolism, lowering LDL-cholesterol and triglycerides and improving post-meal glucose response. However, honey consumption is beneficial for all. Oxidative stress and chronic inflammation play a role in the development of numerous diseases; and honey has a both a strong antioxidant and anti-inflammatory action. Honey has been found to reduce markers of inflammation such as C-reactive protein.

Honey contains 82% sugar and has a glycaemic index of between 45 and 64 and should be used sparingly both because of its impact on blood sugar, but also because it increases the risk of dental caries. Although some research suggests that it is less damaging to teeth than pure white sugar, thought to be due to its antibacterial activity that may deactivate cariogenic bacteria.

References and further reading

[i]  World Health Organization. Guideline: Sugars intake for adults and children. Geneva: World Health Organization; 2015.

[ii]  Gaby A. Adverse effects of dietary fructose. Altern Med Rev. 2005;10: 294-306. Available from:

[iii]  European Food Safety Authority. Scientific Opinion on Dietary Reference Values for carbohydrates and dietary fibre. EFSA Journal. 2010;8(3): 1462.

[iv]  Joint FAO/WHO Expert Committee on Food Additives (JECFA). Steviol glycosides (addendum). In: 69th Meeting of the Joint FAO/WHO Expert Committee on Food Additives. World Health Organization (WHO): Geneva. 2009;60: 183-219.

[v]  Samuel P, Ayoob K, Magnuson BA, Wölwer-Rieck U, Jeppesen PB, Rogers PJ, et al. Stevia leaf to stevia sweetener: exploring its science, benefits, and future potential.  The Journal of Nutrition. 2018;148(7): 1186S-1205S. Available from:

[vi] Syamala Devi N, HariPrasad T, Ramesh K, Merugu R. Antioxidant properties of coconut sap and its sugars. International Journal of PharmTech Research. 2015;8: 160-162.

[vii]  Cianciosi D, Forbes-Hernaández TY, Afrin S, Gasparrini M, Reboredo-Rodriguez P, Manna PP, et al. Phenolic Compounds in Honey and their associated Health Benefits: a Review. Molecules. 2018;23(9). Available from: doi:10.3390/molecules23092322.

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